/Engine/Source/Runtime/Engine/Public/AudioDevice.h
Adds an envelope follower delegate to the submix for this audio device.
virtual void AddEnvelopeFollowerDelegate ( [USoundSubmix](API\Runtime\Engine\Sound\USoundSubmix) * InSubmix, const [FOnSubmixEnvelopeBP](API\Runtime\Engine\Sound\FOnSubmixEnvelopeBP) & OnSubmixEnvelopeBP )